Pollination in Bruguiera gymnorrhiza (Rhizophoraceae) in Miyara River, Ishigaki Island, Japan, and Phangnga, Thailand

Abstract The bird species Hypsipetes amaurotis and Zosterops palpebrosa var. yonakuni , but no insects, were recorded regularly feeding on flower-nectar of Bruguiera gymnorrhiza in the Miyara River Biological Preserve, Ishigaki Island, Japan, at 7:00-9:15 a.m. during the investigation from December 20, 1987, to January 19, 1988. In contrast, Anthreptes malacensis foraged for nectar from 7:00 a.m. to 17:00 p.m. Oriolus chinensis visited the flowers mainly between 6:30 and 7:30 a.m. in Phangnga, Thailand, during the investigation from November 30 to December 19, 1986. Pollen grains were sprayed onto the birds'faces and bills and into the air. The highest mean volume of 0.24 pollen grains/ l /minute was triggered in calm air by the most frequent nectarivore between 6:45 and 7:00 a.m. at a height of 1.5m under a tree-branch carrying 145 fresh flowers in the Miyara River population, Japan. The highest mean volume of 0.27 pollen grains/ l /minute under the same conditions in the Phangnga population, Thailand. Bruguiera gymnorrhiza is bird-pollinated but with the possibility of some pollination indirectly by wind.